Fuel control system for turbojet engines



SUXEXUH KUL LIKUOO [\EFCRCHUE Oct 1954 R. M. KENDIG FUEL CONTROL SYSTEM FOR TURBOJET ENGINES Filed April 25. 1.950

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Q8 min in 05 EN QQW QV 9% ON? nvvszvron RobertMKndi BY ATTORNE Y Patented Oct. 19, 1954 FUEL CONTROL SYSTEM FOR TURBOJ ET ENG INE

Robert M. Kendig, Pittsburgh, Pa, assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application April 25, 1950, Serial No. 157,909

7 Claims.

This invention relates to a fuel control system and more particularly to fluid pressure control apparatus for controlling thrust output from a gas turbo-jet engine.

A main object of the invention is the provision of control apparatus for a gas turbo-jet engine which can be operated to control the thrust output of such an engine according to position of an operators control handle.

Another object of the invention is the provision of thrust control apparatus for a gas turbo-jet engine which will prevent overheating and overspeeding of the gas turbine comprised in such an engine.

Another object of the invention is the provision of a thrust control apparatus such as above defined which is extremely sensitive to changes in speed and temperature of operation of the --gas turbine and rapidly responsive to small increments of such changes when same become critical.

Other objects and advantages of the invention will become apparent from the following more detailed description of the invention.

In the accompanying drawing, the single figure is a schematic representation, partly in outline and partly in section, of a fluid pressure fuel control apparatus embodying the invention.

Description Referring to the drawing, the fluid pressure control apparatus comprises a fluid pressure fuel control valve device I for regulating supply of fuel to the gas turbine combustion chamber (not shown) in response to changes in pressure of fluid; an operators control valve device 2 for regulating the pressure of fluid supplied to the fuel control valve device I a speed responsive control valve device 3 for modifying action of the fuel control valve device I to limit or reduce the amount of fuel to the gas turbine (not shown) when its speed tends to become excessive; a temperature sensitive valve device 4 for modifying action of the fuel control valve device I to so.

limit the amount of fuel to the gas turbine as to prevent its operating temperature exceeding a choosen high degree; an integrating valve device 5 for correlating response of the fuel control valve device I to operation of the operator's control valve device 2, the speed responsive valve device 3 and the temperature responsive valve device 4; and an interlock valve device 6 interposed between the fuel control valve device I and the operators control valve device 2 to prevent supply of fluid under pressure from the latter to the former,

thereby preventing supply of fuel to the gas turbine, until a certain starting speed of the turbine has been attained.

Description of fuel control valve device 1 The fuel control valve device I may comprise a casing having a fuel inlet chamber 8 formed therein which is adapted by means of a port and pipe 9 to be connected to a source of fuel supply (not shown), and having a fuel outlet chamber In formed therein which is adapted by means of a port and pipe II to be connected to such as injection nozzles (not shown) in the gas turbine combustion chamber. The fuel control valve device I further comprises a fuel control valve I2 disposed in chamber 8 and attached to a fluted stem I3 slidably disposed in a casing bore I4 which opens between said chamber 8 and the outlet chamber III. The valve I2 is urged toward a seated position on a casing seat I5 in which it is shown in the drawing by action of a compression spring I6; the valve -I2 when seated, closing communication between the chambers 8 and I0 via the bore I4. To act as a medium through which the valve I2 may be unseated and moved to various positions in proximity to the seat l5 for varying the amount of flow of fuel through the bore I 4', hence -to the turbine, a stem I! is provided. The stem I1 is attached at its one end to the fluted stem I3, thereby to the valve I2, and projects through an accommodating bore I8 opening through a casing partition I9 which separates the fuel outlet chamber II) from a chamber 20 which is constantly open to the atmosphere by way of a port 2I in the casing. In the chamber 20, the stem I1 is attached centrally to a diaphragm follower 23 which is secured for movement with deflection of a diaphragm 24 clamped at its outer periphery between two portions of the casing. The diaphragm 24 is subject opposinglyto atmospheric pressure in the chamber 20 at its one side and to pressure of fluid in a control chamber 26 on its opposite side.

Operation of fuel control valve device 1 In response to pressure of fluid supplied to the chamber 26, the diphragm 24 will be displaced in the direction of chamber 20 an amount according to the degree of such pressure, with consequent unseating and movement of the valve I2, through stem I1, away from the seat I5 a distance according to displacement of the diaphragm and hence also to the degree of pressure in chamber 26 for correspondingly increasing the fiow of fuel between chambers 8 and In via the bore I4. Sub- 3 sequent reduction in pressure of fluid in the control chamber 26 will allow the spring Hi to move the valve l2 accordingly to positions approaching its seat |5 for correspondingly reducing the amount of fuel which may flow from chamber 8 to chamber In by way of the bore M. with a source of fuel at constant pressure supplied to the chamber 8, the amount of fuel which will flow therefrom to the chamber l8, hence to the gas turbine combustion chamber, will be varied according to variation in pressure of fluid in the control chamber 26. A certain minimum pressure in the control chamber 26 will call for zero fuel flow through the fuel control valve device, and a certain maximum pressure will call for a corresponding maximum flow of fuel through said device. Proportionate increase or reduction in pressure of fluid in the control chamber 26 between the above limit pressures will cause proportionate increase or reduction in the amount of fuel allowed by the fuel control valve device to flow to the turbine combustion chamber.

In the fuel control valve device I, to allow for facile movement of the stem l1 and thereby insure sensitivity of response of the device to variations in pressure of control fluid in chamber 26 and to balance off the pressure of fluid in chamber 26, as will be described subsequently, the stem I! is flt loosely in the bore |8 through which it extends and a bellows 38 is provided which encircles that portion of the stem that extends into the chamber 20. One end of the bellows 30 is secured and sealed to the partition l9 encircling one end of the bore I8 while the opposite end of the bellows is secured and sealed to the follower 23. A passage 3| extends longitudinally of the stem I1, opening at its opposite ends into the interior of bellows 38 and into the fuel outlet chamber l so that fuel may flow easily into and out of the bellows 30 from and to chamber l0 during reciprocable movement of the stem H. The size of the passage 3| in stem l'l may be such as will facilitate flow of fuel therethrough; however, should the device tend to oscillate, a choke (not shown) in this passage might be provided to I dampen the oscillation.

During operation of the fuel control valve device in response to variations in pressure of fluid in its control chamber 26, the pressure of the fuel which reaches the delivery chamber I6 and bellows 30 will be proportionate to the amount of fuel flowing to such chamber In, and such pressure within bellows 38 will act on stem l1 and therefore diaphragm 24 in opposition to pressure in the control chamber according to amount of fuel flowing and hence to position of the valve |2. Such pressure of fuel within the bellows 30 together with aid of spring I6 will act to balance off pressure in the control chamber 26 to establish a desired position of the valve |2 relative to seat as will allow the flow of fuel to the delivery chamber H1 in amount commensurate with the degree of control pressure. I

Description of operators control valve device 2 The operator's control valve device 2 may comprise a casing 40 having supply chamber 4| and a delivery chamber 42 formed therein. The supply chamber M is connected to a source of fluid under pressure, such as a reservoir 43, by way of a fluid pressure supply pipe 44 and a constant pressure outlet valve 45. The reservoir 43 may be supplied with fluid under pressure from such as a fluid compressor (not shown). The constant pressure outlet valve 45 will maintain pressure of fluid in supply pipe 44 at a chosen constant value and less than the pressure in the reservoir. The delivery chamber 42 in device 2 is connected to a pipe 21 to convey fluid under pressure thereto and therefrom, for reasons which will hereinafter become apparent.

A supply valve 4'! is provided in the device 2 for controlling communication between the chambers 4| and 42 by way of a bore extending through a casing partition 48 which separates chamber 4| and 42. The valve 4'! is attached to a fluted stem 49 which is slidably disposed in the bore in partition 48. Stem 49 acts to guide reciprocable movement of valve 4'! and allow for flow of fluid under pressure from chamber 4| to chamber 42 when said valve is unseated. A compression spring 50, disposed in chamber 4|, is arranged to urge valve 41 toward a seated position in which it is shown in the drawing for closing off communication between chambers 4| and 42 via the bore in partition 48. To act as medium through which the valve 41 may be actuated to an open position, a stem 52 attached at its one end to fluted stem 49 is provided. The stem 52 extends from the fluted stem 49 through a portion of chamber 42 and an opening in a casing partition 54 which separates the delivery chamber 42 from a diaphragm control chamber 56. The opening in partition 54 through which the stem 52 extends is of such size as will allow considerable clearance area for flow of fluid under pressure to and from chambers 42 and 56. A resilient diaphragm 58 is clamped at its outer edge between sections of the casing 40 to define a flexible central portion which separates the chamber 56 from an exhaust chamber 60 which is constantly open to atmosphere by way of a port 6| in the casing. The diaphragm 58 is provided with an exhaust opening 62 formed in a seat member 64 secured for movement with deflection of the diaphragm by an arrangement of diaphragm follower members. The exhaust opening in member 64 is disposed opposite to the projecting end of the stem 52 which is tapered to fit an accommodating seat formed in said member at the respective end of said opening. The tapered end of stem 52 constitutes an exhaust valve 66 for controlling release of fluid under pressure from the chamber 56 by way of the opening in member 64 and chamber 60. The diaphragm 58 is subject opposingly to pressure of fluid in the chamber 56 and to force of a control spring 68 disposed in chamber 68. An adjustable spring seat 10 is provided to accommodate one end of the spring 68. The seat 10 is-attached to a stem H slidingly extending outwardly of the casing through an opening therein. An cuter projecting end of stem H is provided with a roller follower 12 which is urged into engagement with a cam 13, pivotally connected, by means of a pin I4, to an outwardly projecting arm formed in thecasing. An operators handle 15 is attached to the cam 13 for effecting rocking movement of same about the pin 14 to cause reciprocable movement of the stem H and attached spring seat 10.

Operation of operators control valve device 2 In operation of the operators control valve device 2, with chamber 4| therein charged with fluid at a pressure determined by the constant pressure outlet valve 45, when the operator's handle 15 is in the position in which it is shown in the drawing, titled Zero Thrust" for example, the seat 18 attached to stem 1| will be so positioned that initial compression of spring 68 will be at a minimum, the member 64 carried by diaphragm 58 will be disposed away from the exhaust valve 88, so that chamber 56 and hence the delivery chamber 42 and pipe 2" will be vented to atmosphere by way of the opening in said member 54, the chamber 58, and port 61, and the supply valve 41 will be seated by action of the spring 58. Movement of the handle I5 to positions in the direction of and including a Full Thrust position, indicated by a dot-anddash line so titled in the drawing, will cause movement of the stem 'II inwardly of the casing respective distances according to the degree of handle movement, carrying the spring seat 18 with it. It will be seen, therefore, that the respective end of the spring 58 will be advanced in the direction of the diaphragm 58 along with the seat I8 carried by stem II. Initial movement of the spring seat 18 as above will carry spring 68 with it as the member 64 is caused to seat on the exhaust valve 66, thus closing off the chamber 55, hence the delivery chamber 42 from the exhaust chamber 68. Subsequent movement of the spring seat I8 as above, will cause, through resultant compression of the spring 68 and through the medium of stems 52 and 49, unseating of the supply valve 41 against action of the spring 58. Fluid under pressure from the chamber 4I then will flow by way of the unseated valve 41 into the chamber 42 and by way of the opening in the partition '54 into chamber 56. As a result of such flow thereto, the pressure of fluid in the chamber 56 increases and, with the aid of the spring 58 it will overcome the compressive force of the splng 58 and cheat movement of the diaphragm 58 and thereby member 64 in the direction of chamber 68 until the valve 41 is seated by spring 58, whereupon further increase in pressure thereby will be terminated. The pressure at which the valve 4'! will thus close will depend upon the degree of compression of the spring 58, which in turn is dependent upon position of the seat I8, which is in turn dependent upon the degree of depression of stem II, which is dependent upon the position of the'cam I3, which lastly, is dependent upon position of the handle I5. Thus it will be seen that for any particular position of the handle there will be a particular pressure established in the delivery chamber 42 at the time the supply valve 41 seats. The pressure of fluid thereby established in the chamber 42 will increase from a minimum to a maximum as the handle I5 is moved from its Zero Thrust" position to its Full Thrust position. Conversely, it will be understood that movement of the handle I5 from its Full Thrust position to its Zero Thrust position will eflect decrease in pressure of fluid in the chamber 42 from a maximum to a minimum, respectively. The relationship between movement of the handle 15 and pressure in chamber 42 is determined by the profile which the cam 13 is given; such profile will be described in more detail hereinafter.

Description of speed control valve device 8 The speed responsive valve device 3 may comprise a casing portion 88 having formed therein a fluid pressure supply chamber BI connected to a branch of the fluid pressure supply pipe 44, so that said chamber will be constantly charged with fluid at constant pressure. A bellows 82 connects the casing portion 88 with a casing portion 83. The casing portion 88 is adapted to be fixed relative to casing portion 83; a mounting flange 84 being attached to portion 88 which is provided with bolt holes to allow for securing the flange to a fixed member of such as a turbo-jet engine. By longitudinal collapse and expansion of the bellows 82, the casing portion 83 freely may be moved toward and away from the casing portion 88. A fluid pressure delivery chamber 81 is defined by the inner wall of the bellows 82 between casing portions 88 and 83. A bore 88 formed in casing portion 88 extends between the supply chamber 8| and the delivery chamber 81. A supply valve 89, disposed in the supply chamber Si, is provided to control communication between said supply chamber and the delivery chamber 8'! by way of the bore 88. A tapered seat is formed in casing portion 88 encircling the respective end of the bore 88 to accommodate the supply valve 89 when seated. A compression spring 88, disposed in chamber BI, is arranged to urge the supply valve 88 toward its seated position, in which it is shown in the drawing, for closing off the supply chamber from the bore 88. A stem 81 attached to the supply valve 89 extends through the bore 88 and projects into the delivery chamber 81; the projecting end of the stem being conical in shape to serve as an exhaust valve 92. An exhaust valve seat element 93 projects from the casing portion 83 into the chamber 81 in alignment with the exhaust valve 82. An exhaust passage 84 extends from an opening at theprojecting end of the seat element 93 into casing portion 88 where it extends outwardly terminating at an opening to the atmosphere. A tapered annular exhaust valve seat is formed in the projecting end of the seat element 93 encircling the open end of exhaust passage 94 to accommodate the exhaust valve 92. To actuate the valves 89 and 92 according to speed of the gas turbine in the turbo-jet engine, fly-ball type of mechanism is provided, which, for sake of illustration, may comprise a head 95 adapted to be connected for rotation with the gas turbine through such as a gear 96. A collar element 81 is provided which has an attached stem 98 reciprocably and rotatably disposed in an accommodating bore 98 in the head 95. The casing portion 83 is adapted to be actuated by reciprocable movement of the element 91 through the medium of such as a ball thrust bearing I88 which will allow element 81 to rotate with ease relative to portion 83. Accommodating sockets in the element 91 and portion 83 provide for disposition and retention of the bearing I88. For actuating the collar element 81 and thereby the head portion 83 fly-ball weights I8l are provided. Each weight ml is attached to one end of a respective arm I82 which is pivotally connected by means of a pin I83 to a respective projecting element I84 attached to the head 85. The opposite end of each arm I82 slidably engages a face of the collar element 81. Arrangement of weights I M and arm I82 is such that rotation of the weights with the head 95 will cause the arms to exert a force on the collar element which will urge same toward casing portion 83.

Operation of speed control valve device 3 In operation of the speed responsive valve device 3, when the supply chamber BI is charged with fluid under pressure and the head 85 is being rotated by the gas turbine, corresponding rotation of the weights I8I will cause a centrifugal force to be generated which the arms I82 will transmit to a face on the collar element 91 proportional to the speed of such rotation. The

force thus transmitted to the collar element 91 will cause the casing portion 83 to move in the direction of chamber 81, seating the exhaust valve 9I, thereby closing off the chamber 81 from the atmosphere, and then unseating the supply valve 89. Fluid under pressure from the supply chamber 8I will then flow past the unseated supply valve 89, through the bore 88, into the chamber 81 where the pressure condition therein will thus be increased. The increasing pressure of fluid in the chamber 81 will act on an exposed face I06 of the casing portion 83, thereby generating a force acting thereon which opposes the centrifugal force transmitted by the arms I02 acting on the collar element 91. When the pressure force acting on the body portion 83 substantially equals the centrifugal force acting on the collar element 91, the spring 90 will seat the supply valve 89 while the exhaust valve 92 remains seated on the seat element 93, thereby closing off the delivery chamber 81 from the supply chamber 8| while the former remains closed to the exhaust passage 94. During such closure of the supply valve 89, through extension of the bellows 82, the body portion 83 and collar element 91 will move in a direction in which stem 98 moves inwardly of the bore 99 a distance suflicient to allow for seating of said supply valve. The pressure of the fluid thus held in the delivery chamber 81 will be proportional to the speed of rotation of the head 95, hence of the gas turbine to which the head is assumed to be driven, since such pressure causes closure of the supply valve 89 when it balances the opposing centrifugal force acting on collar element 91, which force is proportional to the speed of rotation of the head 95. A decrease in speed of rotation of the head 95, reflecting a decrease in speed of rotation of the gas turbine, will proportionately reduce the centrifugal force exerted by arms I02 on the collar element 91, whereby the force of the pressure of fluid in the chamber 81 acting on body portion 83 will become preponderant over the above-mentioned centrifugal force and move the body portion 83 and collar element 91 in the direction of the head 95, carrying seat element 93 away from the exhaust valve 92, whereupon some fluid under pressure will flow from the chamber 81 by way of passage 94 until the pressure of such fluid in chamber 81 becomes reduced to a degree which will substantially balance the centrifugal force on collar element 91 whereupon seat element 93 will move against exhaust valve 92 to hold the pressure of fluid in chamber 81 at its new value corresponding to the reduced speed of the head 95. It will thus be seen that in the speed responsive valve device 3 the pressure of fluid in its delivery chamber 81 will be maintained at a pressure proportional to the speed of rotation of the head 95, hence of the gas turbine, for example, to which it is operably connected.

Description of temperature sensitive valve device 4 The temperature sensitive valve device 4 comprises a pneumatic pyrometer to provide fluid at a pressure directly proportional to the temperature of the hot expansible gases being supplied to the gas turbine, and an anticipating relay valve means for controlling a fluid pressure communication between the pneumatic pyrometer and the integrating valve device and for anticipating changes in pressure in the pyrometer, for reasons which will hereinafter become obvious.

The pneumatic pyrometer comprises a casing having a fluid pressure supply chamber H0 formed therein which is adapted to receive fluid under pressure from such as a branch of the pipe 44 by way of a casing passage III. A resilient diaphragm H2 is provided, clamped at its outer periphery between two portions of the casing. The diaphragm I I2 is subject opposingly to pressure of fluid in a chamber H3 at one side and to pressure of fluid in a chamber H4 at its opposite side. A supply valve H5 is provided, disposed in the supply chamber H0 for controlling communication through a casing bore H6 extending from said supply chamber to the chamber H3. The valve H5 is operably connected to the diaphragm H2 through the medium of a stem I I1 extending through the bore I I6. One end of the stem H1 is attached to the valve H5 while the opposite end rockably rests in a follower element H8 carried by the diaphragm. A tapered coil spring I20 disposed in the supply chamber H0 is arranged to urge the stem H1 into engagement with the follower element H8. The diameter of the stem H1 is considerably less than the diameter of the bore I I6 to allow for flow of fluid under pressure in the clearance space therebetween while at the same time allowing for self-alignment of the valve H5. The tapered spring I20 abuts a casing shoulder at its larger end and abuts the valve I I5 at its opposite end so that the valve is thereby centered relative to an opening I22 of the bore H0 which opens into the chamber I I0. Proximity of the valve H5 to the opening I22 determines the flow area which will be available to the fluid under pressure in chamber H0 for flow through bore H6 into chamber H3. A compression spring I24, disposed in the chamber H4, is arranged to bias the diaphragm H2 in the direction of chamber H3. One end of the spring I24 is located in an annular recess formed in the casing while its opposite end abuts a diaphragm follower I25 which is provided with a central projecting portion around which the respective end of the spring fits for location thereby. A passage I28 communicates between the chambers H3 and I I4 for conveying fluid under pressure from the former to the latter. A needle valve I30 is provided in passage I28 to regulate the volume of fluid under pressure which may flow from chamber H3 to chamber H4. Needle valve I30 is attached to a stem in screwthreaded attachment with the casing and projecting outwardly thereof. The outer end of the stem may be turned manually to advance or withdraw the needle valve I30 into and out of an opening I3I which forms a part of passage I28 at its junction with chamber H3. The area presented to fluid under pressure from chamber I I3 for flow to chamber I I4 may thus be carefully adjusted for reasons which will hereinafter become obvious.

In order to sense the temperature of a medium such as the hot expansible gases of the gas turbine, as a chosen example, capillary tube or tubes 1 I33 attached to the casing are provided for projection into the path of flow of such gases. The tubes I33 provide continuous restricted passages I34 which open the chamber H4 to the atmosshock and vibration caused by the hot gases passing over them at high velocity. A tube (not shown)) of larger internal diameter provided with a choke at its outer projecting end might be substituted for the plurality of smaller tubes I33.

Operation of above described portion of temperature sensitive device 4 In operation of the pneumatic pyrometer portion of the device 4, with the supply chamber I I connected to a source of fluid at a substantially constant pressure and with the tubes I33 extending through the path of flow of hot expansible gases entering the gas turbine, and with the valve II disposed a distance away from opening I22, fluid under pressure from the supply chamber IIO will flow via the unseated valve and the bore II6 into the chamber I I3. With the needle valve I30 disposed a certain d stance away from opening I3I, fluid under pressure supplied to chamber I I3 will flow by way of such opening and the passage I28 intothe chamber II4, from which a leak to atmosphere will occur by way of passages I34 in tubes I33. According to a feature of the invention, with the constant bias imposed on the diaphragm II2 by the spring I24, the pressure of fluid in the chamber II3 will be maintained at a certain constant value greater than any pressure which may exist in the chamber II4; that is through deflection of diaphragm H2 and thereby movement of valve II5, greater or lesser amounts of fluid under pressure from the supply chamber IIO will flow into chamber II3, as necessary to maintain the constant pressure differential across needle valve I30 between chambers H3 and H4 against the leak to atmosphere through tubes I33. By virtue of the constant diflerential in pressure thus maintained between chambers H3 and H4, for any given adjusted position of the needle valve I30, the volume of fluid flowing from chamber II3 via said needle valve into chamber II4 thence to atmosphere by way of tubes I33 will be constant during equal time intervals. Pressure of fluid in tubes I33, hence in chamber II3, will be directly proportional to the temperature of such fluid, which temperature will depend upon and indicate the temperature of the hot expansible gases to be admitted to the gas turbine, in the present instance. By employment of such a constant volume of flow through tubes I33 to reflect the variations in temperature of a medium, much faster response to such variations in temperature is attained in chamber H3 in form of corresponding pressure variations than can be attained by employment of a constant volume of static fluid contained in a closed bulb due, it is believed, to a lesser heat capacity, a greater area exposed to the hot gases. and certainly to a greater heat transfer coeflicient. The constant volume flow method thus affording pressure variations directly proportional to changes in temperature being sensed simplifies calibration of the device and greatly reduces error ovvr previous pneumatic pyrometers of a variable flow type in which pressure varied approximately as the square root of the temperature, introducing possibility of considerable error at the higher temperatures where equal increments in temperature change produce increasingly greater increments in resultant pressure change.

Description of relay portion of temperature sensitive device 4 The anticipating relay portion of the device 4 10 comprises a casing secured to the casing of the pyrometer portion in such fasion that the supply chamber H0 is common to both and provides a compact assemblage. A bore I in the casing is provided to communicate between the supply chamber H0 and a delivery chamber I4! which is constantly open to a fluid pressure control passage I42 formed in the casing. A supply valve I43 is disposed in the supply chamber IIO for controlling communication between said supply chamber and the delivery chamber I M by way of the bore I40. A tapered seat is formed in the casing around the end of bore I40 opening into the chamber H0 to accommodate the supply valve I43. A compression spring I45 disposed in the supply chamber I I0 is arranged to urged the supply valve I43 toward a seated position in which it is shown in the drawing. A stem I41 of lesser diameter than the diameter of the bore I40 through which it extends is attached at its one end to the supply valve I43 to act as a medium through which same may be unseated against action of spring I45. The opposite end or" the stem I41 is disposed in the delivery chamber MI and is tapered to form an exhaust valve I48. An exhaust valve seat element I50, disposed opposite to and in alignment with the exhaust valve I48, is provided, attached at its one end to a movable abutment I5I disposed within a cavity I52 formed in the casing. The movable abutment I5I is reciprocably connected to the casing through attachment at its outer peripheral edge to one end of a. bellows I53, the opposite end of which is attached to the casing at one end of cavity I52. A fluid pressure exhaust chamber I55 is defined by the inner wall of cavity I52, exteriorly of the movable abutment I5I, and bellows I53. Exhaust chamber I55 is constantly open to the atmosphere by way of an exhaust port I56 opening outwardly through the casing. A bellows I53 is attached at its one end to a projecting end of seat element I and at its opposite end to the casing encircling the opening to the bore I40. The bellows I58 allows for reciprocable movement of the seat element I50 along with abutment I5I and defines an outer wall of the delivery chamber I II and an inner wall of an annular bellows chamber I60 within bellows I53 between a left-hand end wall of cavity I52 and one face of the abutment I5I. The bellows chamber IE0 is constantly open to the control passage I42 by way of a needle valve I5I which is adjustable exteriorly of the casing to vary the area available for flow of fluid under pressure between passage I42 and the bellows chamber I00. An exhaust passage I62, opening into the exhaust chamber I through the abutment I5I, extends longitudinally through the seat element I50 to an opening disposed opposite to the exhaust valve I48. A tapered seat is formed in the projecting end of the seat element I 50 to accommodate the exhaust valve I48.

For actuating the seat element I50 and thereby stem I41 and supply valve I43 a stem I10 is provided which is attached to a resilient diaphragm MI by means of the usual diaphragm follower elements suitably attached thereto. The diaphragm may be suitably clamped at its periphery between two portions of the casing and is subject opposingly to pressure of fluid in a control chamber I15 at one side and to pressure of fluid in a chamber I16 at its opposite side which latter chamber is constantly open to atmosphere via such as a port I11. A casing partition separates chamber I55 from chamber I16 and an opening is provided therein through which the stem I10 extends with clearance. A socket I80 is formed in one face of the abutment to receive the end of the stem I10 which is rounded or tapered to .fit the socket to assure transmission of thrust to the abutment when in engagement therewith. A compression spring I85, disposed in chamber I16 is arranged to bias the diaphragm I1I in the direction of chamber I15 toward a rest position in which it is shown in the drawing and in which the respective diaphragm follower abuts a centrally projecting tip of a portion of the casing forming an end wall I86 of the control chamber I15. In rest position of the diaphragm I1I, the projecting end of stem I10 connected thereto will be disposed a short distance away from the abutment I5I. The control chamber I15 in the anticipating relay portion of the device 4 is constantly open by way of a casing passage I90 to the chamber H4 in the pneumatic pyrometer portion of the device. It will be seen, therefore, that pressure of fluid in the control chamber I15 will be the same as that existing in chamber H4 and will therefore be directly proportional to temperature of the capillary tubes I33, hence to the temperature of the hot gases entering the gas turbine.

Operation of relay portion of temperature sensitive device 4 In operation of the anticipating relay portion of the device 4 in conjunction with the pneumatic pyrometer portion, until the pressure of fluid in the control chamber I 15 attains a value sufficient to overcome the bias of the spring I85, the diaphragm I1I will remain in its rest position with the stem I10 out of engagement with the abutment I5I which will be in the position in which it is shown in the drawin with seat element I50 out of contact with the exhaust valve I48, and the supply valve I43, therefore, will be in its seated position in which it is shown in the drawing. With the supply valve I 43 closed, fluid under pressure in the supply chamber I I cannot reach the delivery chamber I M and with the exhaust valve I48 open said delivery chamber will be vented to atmosphere by way of the passage I62 in seat element I50 and attached abutment II, exhaust chamber I55 and the port I55. Passage I 42 and thereby bellows chamber I50 will be vented to atmosphere by way of the bore I40 and the delivery chamber I4I, as will be appreciated from preceding description.

When the pressure of fluid in the control chamber I15, corresponding to a certain temperature of the capillary tubes I33 and hence of the turbine gases, becomes sufiicient to overcome opposition of the spring I85 the diaphragm I1I will be deflected in the direction of chamber I16 to cause engagement of stem I with the abutment I5I, after which said stem and abutment in moving with continued slight additional deflection of the diaphragm will move seat element I50 into seating engagement with the exhaust valve I48, thereby closing ofi the delivery chamber I4I, hence passage I42 and bellows chamber I60 to the atmosphere.

In employing the device 4 to prevent increase in temperature of the turbine gases above a certain maximum allowed temperature, in a manner as will hereinafter be described, the needle valve I 30 will be adjusted so that pressure of fluid in chambers H4 and I will cause closing of the exhaust valve I48 at a temperature of tubes I33 somewhat less than the maximum allowed temperature of the gases passing over the tubes. The needle valve I30 is so adjusted in order to assure that the anticipating relay portion be brought into operation before the maximum allowed temperature of the gases is reached as the temperature of the capillary tubes I33, hence pressure in connected chambers H4 and I15, will lag the temperature of the gases when the lat ter temperature is increasing rapidly.

When the pressure of fluid in chamber Il5, corresponding to temperature of the capillary tubes I33, increases above that necessary to seat the exhaust valve I48, resultant further deflection of the diaphragm I'II against spring I45, through movement of the stem I10, abutment I5I, attached seat element I50, and the stem I41, will cause unseating of the supply valve I43. Fluid under pressure from the supply chamber I I0 will then flow by way of the unseated supply valve I43 and bore I40 into the delivery chamber MI and control passage I42 and, by way of needle valve I6I, into the bellows chamber I 60 where the pressure of such fluid actin on the abutment I5I will act to oppose action of pressure of fluid in chamber I15 acting on diaphragm I1I. When the pressure of fluid in the bellows chamber I60 acting on abutment I5I, together with action of springs I45 and I85, becomes sufiicient to overcome action of the pressure of fluid in the chamber I15, the abutment I5I will move in the direction of chamber I55, carrying the stem I10 with it and thereby allowing spring I 45 to seat the supply valve I43 while the exhaust valve I48 remains seated. Pressure of fluid in the passage I42 and delivery chamber MI is thus held by closure of the supply valve I43.

When the temperature of the hot gases passing over the tubes I33 increases slowly, the temperature of these tubes will be the same as that of the gases and will increase at the same relatively slow rate, and, it will be appreciated, that the,

pressure of fluid in chambers H4 and I15 therefore will be directly proportional to the temperature of the hot gases and will increase at the same slow rate. Under these conditions, once the supply valve I43 is unseated by action of pressure of fluid in chamber I15, resultant flow of fluid from the supply chamber IIO into passage I42 will have sufllcient time to flow into the bellows chamber I60 to increase the pressure of fluid therein at the same rate as the increase in pressure in chamber I15, and the action of such pressure in chamber I 50 on abutment I5I will be such as will maintain the valve I43 positioned to maintain pressure of fluid in passage I42 in direct proportionality to pressure of fluid in chamber I15, hence in direct proportionality to the temperature of the tubes I33 and therefore of the hot gases, in the present instance.

When the temperature of the hot gases increases very rapidly, there may be instantaneous differences between the temperature of the tubes I33 and that of the gases as the tubes warm up to gas temperature. The temperature of the tubes I33, hence pressure of fluid in chambers I I4 and I15, under the assumed condition, will therefore no longer be directly proportional to the rapidly increasing temperature of the hot gases. The rate of increase in temperature of the tubes I33, hence the rate of increase in pressure in chambers H4 and I15, will reflect the discrepancy between the temperature of the tubes and the temperature of the gases, in other words, the rate at which the temperature of the tubes I33 and the pressure in chambers H4 and I15 will change in a given instant is a measure of the amount of difference between the temperature of the tubes and that of the gases and so indicates the temperature towar which the tubes are headed. Then, once the supply valve I43 is initially unseated by action of the pressure of fluid in chamber I15 which is increasing in rate as above described, fluid under pressure will flow into the passage I42 and by way of the needle valve I6I, will flow into the bellows chamber I60 to oppose the action of pressure of fluid in chamber I15. By virtue of the needle valve I6I, a sufficient restriction to path of flow will be imposed on fluid flowing from passage I42 to bellows chamber I60 that the instantaneous pressure of fluid supplied to passage I42 will exceed that in the bellows chamber I60. The amount that the pressure of fluid in passage I42 is allowed to exceed pressure of fluid in the bellows chamber I60 will depend upon the rate of change in pressure in chamber I15, hence rate of change in temperature of the tubes I33, which, as previously mentioned, was an indication of the gas temperature toward which the tubes were headed. By proper adjustment of the needle valve IGI, the pressure of fluid in passage I42 will be substantially maintained at a direct proportionality to the rapidly changing temperature of the turbine gases even though the temperature of the tubes I33 lags that ofthe gases by a substantial time interval.

Conversely, with both the supply valve I43 and the exhaust valve I48 closed to hold a pressure of fluid in passage I42 in accord with a stable temperature of tubes I33, when the temperature of the gases drops slowly, the temperature of the tubes I33 will be that of the gases and will drop correspondingly as will pressure of fluid in the chambers H4 and I15. Such reduction in pressure in the chamber I 15 will allow spring I85 and pressure of fluid in bellows chamber I60 to effect movement of abutment I5I so that seat element I50 will leave the exhaust valve I48. Fluid under pressure will then release from bellows chamber I60 and passage I42 at substantially the same rate until pressure of fluid in chamber I15 is again preponderant over force of spring I35 and pressure of fluid in the bellows chamber I60, whereupon, through deflection of diaphragm I1I, movement of stem I in engagement with abutment I5I will cause reseating or element I50 on valve I48.

If, reduction in temperature of the turbine gases occurs at a rate faster than can be followed by the tubes I33, such reduction, reflected by a pressure drop in the chamber I15, will result in unseating of the element I50 from exhaust valve I48 to allow for r duction in pressure in passage I42. The action 01' needle valve I6I on release of fluid under pressure from the bellows chamber I 60- Will be such as to allow pressure of fluid, in the passage I42 to reduce in direct proportionality with reduction in temperature of th 2 turbine gases in anticipation of the temperature toward which the temperature of the tube I33 is headed as indicated by the rate of change of the latter temperature.

Whether or not the drop in temperature of the tubes I33, hencedrop in pressure in chamber I15, occurs rapidly, once the pressure of fluid in chamber I drops, and remains below the value required to maintain the seat element I50in engagement with, valve. I48 against opposition of attached to the stem 208.

14 spring I85 and pressure in bellows chamber I00. the diaphragm III will deflect in the direction of chamber I15 to allow element I50 to unseat and remain unseated from valve I48, venting passage I42 to atmosphere via chamber I4I, passage I62, chamber I and port I56.

Summarizing, it will be seen that the device 4 will respond to an increase in temperature of the turbine gases above a desired maximum value to eflect supply of fluid to control passage [42 at a pressure or pressures directly proportional to the temperature of such gases, whether increasing or decreasing above said maximum value and will respond to a decrease in temperature of the gases below the maximum value to effect venting of the control passage [42 to atmosphere.

Description of integrating valve device 5 The integrating. valve device 5, for sake of illustration, schematically, comprises a casing 200 having a supply chamber 20I, a delivery chamber 202 and an exhaust chamber 203 open to atmosphere. Supply and exhaust ports 204, 205, respectively, are formed in partitions at opposite ends of the delivery chamber 202 which separates same from the supply chamber 20I and the delivery chamber 203, respectively. By way of these ports the delivery chamber 202 may communicate with either the supply chamber 20I or the exhaust chamber 203. A valve 206 in the shape of a ball is disposed in the delivery chamber 202 for controlling the degree of opening and closing simultaneously of the delivery chamber 202 to. the supply and exhaust chamber 20Iv and 203 according to proximity of the valve to the ports 204, 205.

Two oppositely extending valve stems 208 and 209 are attached diametrically opposite to the valve 205. The stem 208 extends through the port 204 andv the supply chamber 201 and. slidably fits in an accommodating socket at its projecting end. The stem 209 extends through the port 205, chamber 203, and outwardly through an accommodating opening in the casing 200. Both the stems 208 and 209 are of lesser diameter than the diameter of openings 204 and 2.05 to allow a path for flow of fluid under pressure when the valve 206 is unseated and the ports 204, 205 are therefore open. A light compression spring 2I0 disposed in supply chamber 201, is arranged to bias the stem 200 in a direction urging the valve 206 toward port 205. One end of the compression spring 2I0 abuts an annular face defining an end wall of chamber 20I while the opposite end abuts an annular shoulder formed by a Washer element A compression spring 2I2 is interposed between a yieldable stop element 2I4 and an annular face formed in a sleeve 2I6 attached to an adjustable spring seat element 2I8. The stop element 2 I4 is attached to a rod 220 one end of which abuts the projecting end of the stem 203 while its other end slidably fits in the sleeve 2I6 and is guided thereby. A washer element 22I attached to rod 220 is arranged to engage sleeve 2H5 and thereby define a yieldable movable abutments 225 and 226 in alignment therewith and of equal size is a disk-shaped fixed abutment 236 which is adapted to be flxed relative to abutment 225 and 226; mounting flanges 232 being provided at opposite peripheral edges of the abutment 236. The flanges 232 are provided with bolt or screw holes to allow for securing same to a fixed mounting member (not shown). A second disk-shaped fixed abutment 235 is disposed on the opposite side of movable abutment 226 in alignment therewith and of equal size. Abutment 235 is provided with a flange 236 having bolt or screw holes which adapt it for attachment to the same mounting member to which abutment 230 is attached. Intermediate the abutments 235 and 226 a speed compensating chamber 240 is formed which is defined at its peripheral edge by a bellows 24! attached and sealed at its opposite ends to said abutments and allowing for movement of abutment 226 toward and away from abutment 235. A speed control chamber 243 is formed between abutments 226 and 230. A bellows 244, defines the peripheral wall of chamber 243, attached and sealed at its opposite ends to the peripheral edge of abutments 226 and 230, and allows for facile movement of abutment 226 toward and away from the abutment 230. A temperature compensating chamber 245 is formed between the abutments 236 and 225. A bellows 246 is attached and sealed at its opposite ends to abutments 225 and 230 to define the peripheral wall of chamber 245 while allowing for facile reciprocable movement of the abutment 225 relative to the abutment 230.

In the integrating valve device 5, the speed compensating chamber 240 is constantly connected to the delivery chamber 8! in the speed responsive control valve device 3 by way of a pipe 210 and corresponding passage in the abutment 235; the speed control chamber 243 is connected to the delivery chamber 42 in the operator's control valve device 2 by way of a pipe 21! and corresponding passage in the abutment 236; the temperature compensating chamber 245 is connected to the control passage I42 in the temperature responsive valve device 4 by way of a pipe 212 and a corresponding passage in the abutment 230; the supply chamber 26l is connected to a branch of the pipe 21! by way of a pipe 213 and the interlock valve device 6; and the delivery chamber 262 is connected to the control chamber 26 in the fuel control valve device I by way of a pipe 215.

Operation of integrating valve device It will be seen that, with movable abutments 225 and 226 rigidly connected one with the other in sandwich fashion with respect to the fixed abutments 235 and 230, pressure of fluid in both the speed compensating chamber 240 and in the temperature compensating chamber 245 will oppose action of pressure of fluid in the speed control chamber 243. When equilibrium is established between the pressure of fluid in the speed control chamber 243 and the summation of pressures of fluid in the speed and temperature compensating chambers 246 and 245, the bellows 24!, 244, and 246 will be in their neutral positions in which they are shown in the drawing, with the abutments 225, 226 and casing 206 also so disposed. Under the above conditions, assume the spring seat element H8, and therefore stop element 2|4, to be fixed and to be in what hereinafter will be referred to as a neutral position in which it is shown in the drawing, the spring 2l0 will urge the stem 209 into engagement with the yieldable stop element 2l4 which remains in its neutral position. The ball valve 206 will be disposed in a position in chamber 202 intermediate the supply and exhaust ports 204 and 205, in which position the valve is shown in the drawing, with the delivery chamber 262 consequently open to both the supply chamber 20! and the exhaust chamber 263.

When the bellows 24!, 244 and 246 are in their respective neutral positions, preponderance in pressure of fluid in the speed control chamber 243 over the summation of pressures of fluid in the speed and temperature compensating chambers 240 and 245 will cause upward movement, as viewed in the drawing, of the abutments 225, 226 and casing 266 against the tension-springlike opposition of the bellows 244 and the compression-spring-like opposition of both the bellows 246 and the bellows 2. The degree of such upward movement of the casing 206 will depend upon the degree of such preponderance in pressure and the spring values of the three bellows.

Conversely, when the bellows 24!, 244 and 246 are in their neutral positions, preponderance in summation of the pressures of fluid in both the speed and temperature compensating chambers 246 and 245 over the pressure in the speed control chamber 243 will cause downward movement, as viewed in the drawing, of the abutments 225, 226 and the casing 200 against the compressionspring-like opposition of the bellows 244 and the tension-spring-like opposition of both the bellows 24! and the bellows 246.

Upon equalization of pressure forces acting on movable abutments 225, 226 subsequent to movement thereof in either direction as abovedescribed, the spring-like deflection forces of the bellows 2, 244 and 246 will return the abutments 225, 226 and casing 206 to their neutral positions in which they are shown in the drawing. Partial equalization of such pressure forces will allow partial return.

It will be appreciated from the foregoing that the position which the casing 260 will be caused to assume away from neutral position in either direction is determined by the degree of difference between pressure in chamber 243 and the summation of pressures in chambers 240, 245.

Since the bias spring 2l0 urges the stem 209 to maintain engagement with stop element 2|4, upward movement or downward movement of the casing 260 from its neutral position in which it is shown in the drawing will tend to cause closure of the exhaust port 265 or of the supply port 264, respectively, through engagement of a valve 266 with respective seats formed in the casing encircling these ports. Once the valve 206 engages either of the above seats, continued movement of the casing 206 in the same direction causing such engagement will carry the valve with it; continued upward movement causing stem 209 to leave stop elemer, 2M, and continued downward movement carrying said stop element with the stem and compressing spring 2I2. Return of casing 200 to its neutral position will allow springs 2I0 and M2 to return valve 206 to its neutral position in which it is shown in the drawing.

Closure of the supply port 264 by valve 206 closes off the delivery chamber 202 from the supply chamber 20L while closure of the exhaust port 265 by said valve closes ad the delivery chamber from the exhaust chamber 263.

It will be seen then that preponderance in pressure in the speed control chamber 243 over the sum of the pressures in chambers 240, 245 will cause closure of the exhaust port 205 while the supply port 204 remains open; while a preponderance in pressure in reverse order will cause closing or the supply port 204 with the exhaust port. 205 open.

Description of dampening portion of integrating valve device To modify operation of the valve 206 and pre vent overshooting and undershooting the pressure of fluid supplied to pipe 215, a dampening mechanism is provided.

The dampening mechanism comprises two spaced apart movable abutments 300, 301 rigidly connected one with the other by means of such as a plate 302. The abutments 300 and 301 are disposed at opposite sides of the spring seat element 218 which also is in the form of a flat plate in slidable engagement with the plate 302. The plate 302 is operatively connected to the spring seat element 218 through the medium of a slot 304 in an adjustable element 305 attached to the plate 302 and a roller 306 rotatably attached to said seat element for vertical movement therewith and while permitting rolling contact of said roller with the walls of the slot 304. The element 305 is fixed to plate 302 by means (not shown) which may be loosened to allow the element to be turned to properly orient the slot 304 for proper travel of the roller 306. At opposite ends of the mechanism are provided respective fixed elements 310 and 311 of the same size as and in alignment with the movable abutments 300 and 301, all of which may be substantially disk-shaped. The fixed abutments 310 and 311 are provided with securing arms having bolt or screw holes 312 to allow for securing them to the same mounting member (not shown) to which abutments 230 and 235 are attached. A bellows 314 is provided attached at opposite ends to the abutments 300 and 310 at their peripheral edges to define a chamber 315, while a similar bellows 3l6 is attached at its opposite ends to the abutments 301 and 311 in like fashion to define a chamber 311. The chamber 311 is connected to the delivery chamber 202 by way of a branch of the pipe 215, a corresponding passage in the fixed abutment 31 1 and an adjustable needle valve 325 arranged to control the size of opening available for flow of fluid under pressure from passage 215 into the chamber 311. The chamber 315 is connected to the chamber 31! by way of a pipe 328 and corresponding passages 320a and 3281; in the abutments 310 and 31 respectively. An adjustable needle valve 330 in abutment 310 is provided to'regulate the size of opening available for flow of fluid under pressure into and out of chamber 315 to and from passage 320a.

Operation of dampening portion of integrating valve device 5 In operation of the dampening mechanism, in response to preponderance in pressure l fluid in the chamber 311 over that in the chamber 315 will cause movement of the abutment 301, and thereby plate 302 and abutment 300 in the direction of chamber 315. Such movement of the plate 302 will carry the element 305 with it and cause the slot 304 to be moved in the same direction. Such movement of the slot 304 will cause upward movement of the seat element 210 and stem 209, as viewed in the drawing, thereby causing the valve 206 to be moved toward the supply port 204 to reduce or close off the area available for flow of fluid under pressure from the supply chamber 201 to the delivery chamber 202. Conversely, a preponderance in pressure of fluid in the chamber 315 over that in the chamber 311 will cause movement of the abutment 300, hence abutment 301 and plate 302, in the opposite direc tion toward chamber 311. Such movement of the plate 302 in carrying the element 305 with it will cause the slot 304 to be moved in the same direction, moving the roller 306, hence seat element 2 i0, downwardly as viewed in the drawing. Downward movement of seat element 218 will allow stem 209 and valve 203 to follow it, opening supply port 204 and tending to or closing off exhaust port 205.

The dampening mechanism will be so tuned by adjustment of needle valves 325 and 330 that it will move valve 206 toward the supply port 204 according to the rate of increase in pressure in pipe 275 to prevent excessive overshooting of such pressure, and will move valve 203 toward the exhaust port 205 according to rate of decrease in pressure in the pipe 215 to prevent excessive undershooting of such pressure.

Description of interlock valve device 6 The interlock valve device 3 may be substantially like the fuel control valve device 1 in structure. schematically, the interlock valve device 6 may comprise a casing 400 having an inlet chamber 401 connected to a branch of the pipe 211 and an outlet chamber 402 connected to the pipe 273. A valve 403, disposed in the inlet chamber 401, is provided for controlling communication between the inlet chamber 401 and the outlet chamber 402 by way of a bore 404 extending through a casing partition which separates the two chambers. The valve 403 is attached to a fluted stem 405 which extends through in slidable engagement with the wall of the bore 404. The valve 403 is urged by a spring 406 toward a casing seat encircling the end of the bore 404 which opens into chamber 401. To act as a medium through which the valve 403 may be unseated to open chamber 402 to chamber 401 a stem 400 is provided. The stem 408 is attached at its one end to the fluted stem 405, thereby to the valve 403, and projects through an accommodating bore 409 opening through a casing partition 410 which separates the outlet chamber 402 from chamber 41 1 which is constantly open to atmosphere by way of a port 412 in the casing. In the chamber 4, the stem 408 is attached to a diaphragm follower 415 which is secured for movement with deflection of a diaphragm 410 which is clamped at its outer periphery between two portions of the casing. The diaphragm 413 is subject opposingly to atmospheric pressure in the chamber 411 at its one side and to pressure of fluid in a control chamber 411 on its opposite side. A compression spring 418 is disposed in the chamber 411 and is arranged to bias the diaphragm 410 toward engagement with an annular seat ring 420 which encircles an opening in the wall of chamber 41? which is connected toa branch of the pipe 210.

()peration of interlock valve device 6 When pressure oi fluid in the pipe 210 acting on diaphragm 410 within the area of ring 420 is sufiioiently great to overcome action of the spring 448, the diaphragm 410 will move away from the seat ring, allowing the entire chamber M1 to be pressurized, whereupon the diaphragm 4I6 will rapidly deflect to its maximum extent, unseating the valve 403 and fully opening the outlet chamber 402 to the inlet chamber 40I. Upon a certain subsequent reduction in pressure of fluid in the chamber M1, the spring 4I8 will return the diaphragm 4I6 into engagement with the seat ring 420, allowing the spring 406 to seat the valve 403, thereby closing the outlet chamber 402 to the inlet chamber 40!.

The same type of opening through the stem 408 and bellows arrangement as that described in connection with the fuel control valve device I may be provided in the device 6 to allow for facile movement of the stem 408, eliminating the usual sealing rings.

Operation of control apparatus Assume that the turbo-jet engine is idle and that it is desired to operate same. Assume also that the reservoir 43 is charged with fluid under pressure, as therefore will be the supply pipe 44, as therefore will be chambers 4|, 8| and H in the operator's control valve device 2, in the speed responsive valve device 3, and in the temperature responsive valve device 4, respectively. Assume that the handle 15 of the operators control valve device 2 is in its Zero thrust position, in which case the pipe 21!, hence the control chamber 243 in the integrating valve device 5, will be vented to atmosphere by way of the device 2, as will be appreciated from previous description. Since the turbo-jet engine is assumed to be idle, the head 95 of the speed responsive valve device 3 will also be idle so that the pipe 210, hence the control chamber M1 in the interlock valve device 6 and the speed compensating chamber 240 in the integrating valve device 5, will be vented to atmosphere by way of the said speed responsive device, as will be appreciated from previous description. With its control chamber 4|1 vented, the interlock valve device 6 will assume the position in which it is shown in the drawing, closing off the pipe 213 to the pipe 21I. Also, since the engine is idle, the turbine inlet temperature will be low so that the control pipe 212, hence the temperature compensating chamber 245 in the integrating valve device 5, will be vented to atmosphere by way of the temperature sensitive valve device 4, as will be appreciated from previous description of the latter device. The pipe 215, hence the control chamber 26 in the fuel control valve device I, will be vented to atmosphere by way of the integrating valve device 5, since its chambers 202, 240, 243 and 245 are vented to atmosphere. The casing 200 and valve 206 will be in their respective neutral positions, as will be appreciated from previous description, as also will be the seat element 2I8, since pipe 215 is vented. With its control chamber 26 vented, the fuel control valve device I will be in the position in which it is shown in the drawing, closing off the fuel supply pipe 9 from the combustion chamber delivery pipe II.

Assume now that it is desired to start and to operate the turbo-jet engine. The turbine and compressor will be turned over by means not shown and the operator will move the operator's handle 15 out of "Zero Thrust position to some position in the direction of Full Thrust, whereupon the device 2 will respond to supply fluid to pipe 21I at a certain pressure in accord with the position of said handle. sure in pipe 21! will flow to the control chamber 243 in integrating valve device to cause open- Such fluid under pres-- ing the supply port 204 and closure of exhaust port 205 while the speed responsive valve device 3 responds to turning over of the engine to effect supply of fluid to the chamber 4 I 1 in device 6 and to the chamber 240 in the integrating valve device at increasing pressures directly proportional to the increasing speed of rotation of the engine. With the chamber 20I in the integrating valve device 5 cut off from the source of fluid under pressure, such as the pipe 21I, by the device 6, even with the supply port 204 in device 5 open, the control chamber 26 in the fuel control valve device I will remain devoid of fluid under pressure so that the fuel will remain cut off to the engine. When the turbo-jet engine being turned over by the starting means (not shown) attains a speed such as 3000 r. p. m., for example, the resultant increase in pressure of fluid from the speed responsive valve device 3 in the control chamber 4" in device 6 will be sufilcient to unseat valve 403 to open the pipe 213 to the source of fluid under pressure such as present in pipe 21I. Fluid under pressure will then flow via the pipe 213, chambers 20I and 202 in the integrating valve device 5, and the pipe 215 into the control chamber 26 in the fuel control valve device I to cause the valve I2 to be opened to allow fuel to flow from pipe 9 into pipe II to the turbo-jet engines combustion chamber at a rate commensurate with the degree of pressure of the fluid supplied to the chamber 26. Such fuel will be ignited in the combustion chamber to generate hot expansible gases which operate the engine, whereupon the starting means will be cut off. So long as the supply port 204 in the integrating valve device 5 remains open, fluid from pipe 213 will flow to the control chamber 26 in the fuel control valve device I, increasing the pressure therein and causing a corresponding increase in rate of fuel supply to the engine whose speed will increase accordingly. In response to increase in engine speed, the device 6 will increase the pressure of fluid supplied to the speed compensating chamber 240 in the integrating valve device 5. When the speed of the engine becomes great enough, the pressure of fluid in the chamber 240 in device 5 will equalize with that in the control chamber 243, causing movement of the easing 200 to a position wherein the valve 206 will occupy an equilibrium position intermediate the supply and exhaust ports 204 and 205 such that the pressure of fluid in the control chamber of the fuel control valve device I will be held at the pressure which allows the desired rate of fuel flow to the engine to maintain its speed of operation in accord with the desired speed as called for by pressure of fluid in the integrating valve device chamber 243 and by position of the operators handle 15. Since thrust produced by the turbo jet engine is a function of speed, the position of the handle may be graduated in terms of thrust.

In like manner, by movement of the opera tors handle 15 toward up to Full Thrust position. the pressure of fluid in the integrating valve device speed control chamber 243 will be increased up to a maximum value to shift casing 200 to close exhaust port 205 allowing fluid under pressure from pipe 213 to flow to the control chamfer of the fuel control valve device I to increase fuel supply to the engine until the resultant increase in its'operational speed causes a corresponding increase in the pressure of fluid in the integrating valve device speed compensating chamber 240 suflicient to balance off the increased pressure in chamber 243 whereupon casing 200 will again be returned to a position in which the valve 206 will be so disposed relative to supply and exhaust ports 204 and 205 as to maintain the pressure in the fuel control valve device chamber 26 at the proper value necessary to hold the proper balancing pressure in the integratin valve device chamber 240. If, for any reason, the speed of operation of the engine should tend to increase above that called for by position of the operators handle 15 and therefore by the pressure of fluid in the integrating valve device speed control chamber 243, any undesirable increase in engine speed will result in a corresponding increase in pressure of fluid in the integrating valve device speed compensating chamber 240 which will overcome action of pressure of fluid in the chamber 243 to move casing 200 in the direction tending to close the supply port 204 and to open the exhaust port 205 to reduce the pressure in the fuel control valve device control chamber 28 to so reduce fuel supply to the engine as to prevent such undesired increase in engine speed. In Full Thrust position of the operators handle 15, a maximum engine speed of 12,500 r. p. m. for example, may be called for and the control apparatus will respond as above described to prevent an increase in operating speed above this value.

Should the operating temperature of the gas turbine comprised in the engine tend to exceed a chosen degree, such as 1750 F'., for example, it will be appreciated from previous description that the temperature sensitive valve device 4 will respond to effect pressurization of the integrating valve device temperature compensating chamber 245 to such an extent that it will act with pressure of fluid in the speed compensating chamber 240 to overcome action of pressure of fluid in the speed control chamber 243 to so move the casing 200 as to position the supply port 204 closer to valve 206 and the exhaust port 205 further away from said valve to cause suflicient reduction in the fuel control valve device control chamber 26 as will effect reduction in fuel supply to the engine as will prevent the turbine operating temperature from exceeding the maximum desired value.

In response to movement of the operators handle 15 in the return direction toward or to Zero Thrust position, pressure of fluid in the integrating valve device speed control chamber 243 will be reduced in degree in accord with degree of such movement. The reduction in pressure in chamber 243 will result in preponderance in pressure of fluid in the speed compensating chamber 240 and resultant movement of the casing 200 relative to valve 206 as to further close the supply port 204 and to further open the exhaust port 205 so as to release sufiicient fluid under pressure from the fuel control valve device control chamber 26 as will reduce the pressure of fluid therein to a value which will so regulate fuel supply to the engine that its speed, hence its thrust, will be commensurate with the reduced pressure of fluid in the speed control chamber 243. When pressure of fluid in the speed control and speed compensating chambers 243, and 240, again substantially equalize, an equilibrium position of the casing 200 relative to valve 205 will be established in which supply of fluid under pressure into chamber 202 from chamber 20! is properly balanced with release of fluid under pressure from chamber 202 into exhaust chamber 203' to maintain the proper pressure of fluid in Summary It will now be seen that I have provided a fluid pressure control apparatus for controlling the thrust-output of a gas turbo-jet engine. By means of such apparatus, the thrust may be accurately controlled and means are provided in the apparatus which will prevent the speed and temperature of operation of the gas turbine from becoming excessive.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. Fuel control apparatus for a fuel burning engine comprising in combination, valve means for regulating flow of fuel to said engine, control means comprising movable abutment means subject opposingly to two different fluid pressures and arranged for operation by a preponderance in one to effect operation of said valve means to increase supply of fuel to said engine and upon balancing of the one by the other to prevent further supply of fuel to said engine, an operators control valve device for providing said one fluid pressure on said abutment means, and means responsive to engine operating temperature above and below a certain value to establish and disestablish, respectively, the other of said two fluid pressures on said abutment means.

2. Fuel control apparatus for a fuel burning variable speed engine comprising in combination,

valve means for regulating supply of fuel to said engine, means including an operators control device for effecting operation of said valve means to supply fuel to said engine, control means controlling the operative connection between said opera'tors control device and said valve means, and means responsive to speed of said engine for effecting operation of said control means to disestablish and establish said operative connection below and above, respectively, a chosen speed of said engine.

3. Fuel control apparatus for a fuel burning variable speed engine comprising in combination with a source of fuel under pressure and a source of control fluid under pressure, fuel control valve means for regulating supply of fuel from said source of fuel to said engine, a valve device controlled by two opposing pressures operative by preponderance of one to effect operation of said valve means to increase supply of fuel to said engine and by balancing against the other to limit the supply of fuel according to said one pressure, an operators control device controlling communication between said source of control fluid and said valve device for increasing said one pressure, speed responsive means driven by the engine, and otLer valve means operative by said speed responsive means and controlling communication betwe.-n said source of control fluid and said valve device for increasing said other pressure in accord with increase in speed of said engine.

4. Fuel control apparatus for a fuel burning variable speed engine comprising in combination with a source of fuel under pressure and a source of control fluid under pressure, fuel control valve means for regulating supply of fuel from said source of fuel to said engine, a valve device controlled by two opposing pressures operative by preponderance of one to eifect operation of said valve means to increase supply of fuel to said engine and by balancing against the other to limit the supply of fuel according to said one pressure, an operators control device controlling communication between said source of control fluid and said valve device for increasing said one pressure, speed responsive means driven by the engine, other valve means operative by said speed responsive means and controlling communication between said source of control fluid and said valve device for increasing said other pres sure in accord with increase in speed of said engine, and means subject to said other pressure to prevent operation of said fuel control valve means to supply fuel to said engine when said other pressure is less than a chosen degree.

Fuel control ap,. .ar'itus for a variable speed fuel burning engine, comprising in combination with a source of fluid under pressure, a fuel control valve device having a fuel supply inlet adapted to be connected to a source of fuel under pressure and a fuel supply outlet adapted to be connected to said engine and comprising means for controlling the degree of opening of said outlet to said inlet according to degree of pressure of fluid in a control chamber; an operators control valve device having a supply cham-- ber connected to said source of fluid under pressure, a delivery chamber, and an exhaust chamber open to atmosphere and comprising means controlling communication between said chambers to regulate degree of pressure of fluid in its delivery chamber according to position of an operators handle, a speed responsive valve device adapted to be driven by said-engine and having a supply chamber connected to said source, an exhaust chamber open to atmosphere, and a delivery chamber and comprising means controlling communication between its chambers to regulate the degree of pressure in its delivery cham ber according to speed of operation of said ensine, and an integrating valve device having a delivery chamber connected to the control chamber in said fuel control valve device, an exhaust chamber open to atmosphere, a supply chamber and a speed control chamber both connected to the delivery chamber in said operators control valve device, and a speed compensating chamber connected to the delivery chamber in said responsive valve device, said integrating valve device comprising means including valve means to control opening and closing of its deliery chamber to its supply and exhaust chamaers according to degree of diiferential in pressures in its speed control and speed compensating chambers.

6. Fuel control apparatus for a variable speed fuel burning engine, comprising in combination with a source of fluid under pressure, a fuel control valve device having a fuel supply inlet adapted to be connected to a source of fuel under pressure and a fuel supply outlet adapted tobe connected to said engine and comprising means for controlling the degree of opening of said outlet to said inlet according to degree of pressure of fluid in a control chamber; an operators control valve device having a supply chamber 0onnccted to said source of fluid under pressure, a delivery chamber, and an exhaust chamber open to atmosphere and comprising means controlling communication between said chambers to regulate degree of pressure of fluid in said delivery chamber according to position of an operators handle, a speed responsive valve device adapted to be driven by said engine and having a supply chamber connected to said source, an exhaust chamber open to atmosphere, and a delivery chamber and comprising means controlling communication between its chambers to regulate the degree of pressure in said delivery chamber according to speed of operation of said engine; and an integrating valve device having a delivery chamber connected to the control chamber in said fuel control valve device, an exhaust chamber open to atmosphere, a supply chamber and a speed control chamber both connected to the delivery chamber in said operators control valve device, and a speed compensating chamber connected to the delivery chamber in said speed responsive valve device, said integrating valve device comprising means including valve means to control opening and closing of its delivery chamber to its supply and exhaust chambers according to degree of differential in pressure in its speed control and speed compensating chambers, and dampening means associated with said valve means sensitive to rate of change of pressure in the delivery chamber of said integrating valve device to prevent overshooting and undershooting of such pressure.

'7. Fuel control apparatus for variable speed fuel burning engine, comprising in combination with a source of fluid under pressure, a fuel control valve device having a fuel supply inlet adapted to be connected to a source of fuel under pressure and a fuel supply outlet adapted to be connected to said engine and comprising means controlling the degree of opening of said outlet to said inlet according to degree of pressure of fluid in a control chamber; an operators control valve device having a supply chamber connected to said source of fluid under pressure, a delivery chamber, and an exhaust chamber open to atmosphere and comprising means controlling communication between said chambers to regulate degree of pressure of fluid in said delivery chamber according to position of an operators handle, a speed responsiveyalve device adapted to be driven by said engine and having a supply chamber connected to said source, an exhaust cham ber open to atmosphere, and a delivery chamber and comprising means controlling communication between its chambers to regulate the degree of pressure in its delivery chamber according to speed of operation of said engine; a temperature responsive valve device having a supply chamber connected to said source, an exhaust chamber connected to atmosphere, and a delivery chamber and comprising means adapted to sense the temperature of hot gases in said engine to control communication between its delivery chamber, supply chamber, and exhaust chamber to regulate the degree of pressure in its delivery chamber according to temperature of operation of the engine; and an integrating valve device having a delivery chamber connected to the control chamber in said fuel control valve device, an exhaust chamber open to atmosphere, a supply chamber and a speed control chamber both connected to the delivery chamber in said operators control valve device, a speed compensating chamber connected to the delivery chamber in said speed responsive valve device, and a temperature compensating chamber connected to the delivery chamber insaid temperature responsive valve ,device, said integrating valve device comprising means including valve means to control communicationbetween its delivery chamber and its 25 supply and exhaust chambers according to degree of differential in pressure between its speed control chamber and its speed and temperature compensating chambers.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,227,666 Noack Jan. '7, 1941 2,404,428 Bradbury July 23, 1946 2,422,808 Stokes June 24, 1947 2,474,033 Chamberlin et a1. June 21, 1949 2,479,813 Chamberlin et a1. Aug. 23, 1949 2,485,514 Sturrock Oct. 18, 1949 2,499,232 Strub Feb. 28, 1950 Number Number 15 620,161 634,095

Name Date Ifield Apr. 4, 1950 Hughes Aug. 29, 1950 Mallory Sept. 12, 1950 Ifield et a1 Oct. 3, 1950 Mock Nov. 28, 1950 Gregory et a1 Dec. 26, 1950 Mordell et a1. Jan. 16, 1951 Ifield et a1. Mar. 6, 1951 Mock Jan. 1, 1952 Mock Jan. 1, 1952 FOREIGN PATENTS Country Date Great Britain Mar. 21, 1949 Great Britain Mar. 15, 1950 

